1. Field of the Invention
The present invention relates to a liquid crystal display (LCD) apparatus, and particular to an LCD which solves a problem of a spacer which is provided to ensure a space between a pair of attached substrates.
2. Description of the Prior Art
A liquid crystal display (LCD) apparatus is made by attaching to a pair of electrode substrates, predetermined electrode wires formed thereon while leaving an intervening space, and pouring liquid crystal into the space to be enclosed therein. The resultant LCD has a capacitor using the liquid crystal as a dielectric layer of a display pixel. Such an LCD is used as a display for office automation and audio visual equipment because of its advantageously small, thin size and low power consumption.
Referring to FIG. 4 which is a plan view of an LCD, the LCD has a lower substrate 1, an upper substrate 2, a sealing member 3, a spacer 4, an opening 5, an enclosing member 6, and a pixel area 7. Electrodes on one side of display pixel capacitor is formed on the substrate 1, and the electrodes on the other side are formed on the substrate 2. The substrates 1 and 2 are attached to each other around the edges thereof using the sealing member 3. The spacer 4 is provided between the substrates 1 and 2 so as to ensure a space between them. The sealing member is partly cut off to thereby form the opening 5 via which liquid crystal is poured into the space between the substrates 1 and 2. The enclosing member 6 encloses the liquid crystal in the space between the substrates 1 and 2. The pixel area 7 is provided with color filters for coloring light which passes through the display pixel capacitor and respective display pixels for color displaying.
Lower and upper substrates 1 and 2 are generally made in the form of a mother substrate including a number of such substrates 1 and 2. The lower substrate 1 generally provided with dispersing spacers 4 is attached to the upper substrate 2 coated with a sealing member. The laminated substrates 1 and 2 are pressed and heated to thereby harden the sealing member 3, so that a number of continuous bodies (receptacles for liquid crystal) for LCD apparatuses are made which have a predetermined width including a thin space inside. After separating the bodies, liquid crystal is poured into each thin space via the pouring opening 5, and the opening 5 is enclosed by enclosing a member, whereby an LCD apparatus is finished.
In the LCD apparatus shown in FIG. 4, light-less phenomenon is observed in the area near the pouring opening 5 in the pixel area 7, i.e., a light-less area 8.
Referring to FIGS. 5 and 6 which are an enlarged plan view and a cross sectional view along the line VI--VI in FIG. 5, respectively, of an area near a light-less area 8, color filters are arranged in a matrix corresponding to respective display pixels, and spacers 4 are gathered around the lower edge, i.e., on the pouring opening 5 side, of the color filter 11. The gathered spacers 4 may cause a color-less phenomenon.
The reason for the gathered spacers 4 may be considered as follows. Since a color-less phenomenon due to gathered spacers 4 is observed before liquid crystal is poured into the intervening space of the substrates 1 and 2, it is known that the spacers 4 had gathered before the step of attaching the substrates 1 and 2. Here, the particle diameter 4 of each spacer 4 is determined according to elasticity of the spacer 4, the width of the intervening space of the substrates 1 and 2, i.e., a cell gap, and a given pressure. With the substrates 1 and 2 attached to each other, spacers 4 are sandwiched by them in a slightly deformed shape due to the pressure. The width of the intervening space with a color filter of about 1 .mu.m thickness is different from that of the intervening space without a color filter. That is, a cell gap is different between where there is a color filter exists and where there is not. Note that, when the substrates 1 and 2 which are respectively provided with spacers 4 and sealing members 3 are attached and pressed, the air between the substrates 1 and 2 flows out via the pouring opening 5, causing spacers 4 to move. The spacers 4 at areas without a color filter 11 move more freely as they are pressed only slightly by the substrates 1 and 2, and are discharged via the pouring opening 5. On the other hand, the spacers 4 at areas with a color filter 11 can hardly move as they are pressed strongly by the substrates 1 and 2, and thus move only slightly along the color filter 11. The spacers 4 moving from the area with a color filter 11 to the area without a color filter 11 are also discharged via the pouring opening 5. Therefore, spacers 4 may gather around the area with a color filter 11 closest to the pouring opening 5.